There is a growing focus upon central nervous system factors in antisocial behavior. Studies have reported that delinquents evidence a variety of cognitive deficits, as assessed by neuropsychological tests, but the literature is troubled by small N's, cross-sectional design, bias from highly-selected incarcerated subjects, post-hoc use of tests for research, and failure to demonstrate the specificity of the deficits to delinquency per se, rather than to other childhood problems that accompany delinquency. This project was designed to ask whether some specific patterns of cognitive deficit are prospectively predictive of delinquent behavior, for the first time using self-reported delinquent behavior (SRD) in a large unselected birth cohort and a theory-based research test battery, in order to avoid problems characteristic of earlier research. The cohort studied comprises the 1037 subjects of the Dunedin (New Zealand) Multidisciplinary Health & Development Study. Neurological, health, educational, psychological, social and family data have been collected for the cohort semiannually since birth. The project's first 3 years, supported by a NIH New Investigator Award, consisted of data collection when the subjects were 13 years old, and has produced 18 papers to date. Analyses are yielding evidence that patterns of neuropsychological deficit do exist that relate differentially to early adolescent SRD. Also, the data suggest that cognitive strengths may protect children from criminogenic environments. We are now collecting SRD at age 15, and lifetime police records through age 17. The project proposed herein is a follow-up designed to collect data on self-report delinquency, attitudes toward crime, neuropsychological function, mental health, drug & alcohol use, socio-familial, education & employment, at age 18. The ultimate aim of the project is to test the efficacy of neuropsychological variables, in concert with other pertinent variables, for discriminating nondelinquents, minor delinquents who desist early on, and delinquents who go on to develop serious and recidivistic juvenile offense careers. Knowledge of delinquency-related patterns of cognitive dysfunction may provide information useful toward several goals: (1) Increased understanding of the etiology of delinquency, (2) Identification of specific patterns of deficit which may be targeted for preventive intervention, (3) Addition to the growing list of warning signs for early identification of children at risk for developing seriously delinquent lifestyles, and (4) Provision of information in support of theory construction.